Objective To study the mechanism of high intensity ultrasound (HIU) on COX-2 mRNA expression and apoptosis in breast cancer cell line MDA-MB-231 cells.Methods Human breast cancer cells MDA-MB-231 in vitro were exposed in HIU (50 w/cm2).RT-PCR was performed to detect the level of COX-2 mRNA before and after exposure.The ultrastructural changes in apoptotic cells were examined by transmission electron microscopy.Results The relative level of COX-2 mRNA decreased gradually along with the increase of exposure time and apoptotic bodies in MDA-MB-231 cells considerably increased under electron microscope.When exposure time was increased to 30 seconds,a few cells died.Conclusion HIU promotes apoptosis of breast cancer MDA-MB-231 cells in a COX-2 mRNA depended way.

ObjectiveTo analyze the epidemiological and clinical characteristics of children's lower extremity amputation and amputation rehabilitation, and to explain the causes of children's amputation and the complications after amputation. MethodsFrom January, 2016 to March, 2021, 51 amputation related children were retrospectively analyzed. The correlation between the cause of amputation and complications post amputation were analyzed. ResultsTraumatic amputations accounted for 58.82%, and the main cause was traffic accidents (70%). Amputations caused by diseases accounted for 41.18%, and the main cause was congenital limb deformities (80.95%). Traumatic amputation was more likely to have stump complications than expected (P < 0.05). The possibility of stump complications after disease-specific amputation was lower than expected (P < 0.05). ConclusionTraffic trauma is the main cause of amputation in children and is characterized clinically by a high incidence of unsatisfactory stumps, mainly due to soft tissue abnormalities, and most cases require stump revision to improve the poor residuals for prosthetic restoration of ambulation. Congenital pseudarthrosis of the tibia is the main cause of disease-specific amputation, and the outcome of amputation often cannot be definitely avoided even after long-term limb preservation treatment.